1. Field of the Invention
This invention relates to a compound eye optical system which is capable of forming an image of an object on the image plane while varying the imaging magnification thereof and is also capable of continuous magnification change.
2. Description of the Prior Art
A compound eye optical system forms an erect image of an object by disposing two or more minute imaging element arrays each comprising a plurality of minute imaging elements, e.g. minute lenses, arranged in an array form. The imaging magnification of the compound eye optical system is usually one-to-one magnification, but there are known compound eye optical systems in which the imaging magnification is not one-to-one magnification by making different the spacings between the minute imaging elements of the minute imaging element arrays forming the compound eye optical system. However, any of these compound eye optical systems is fixed in imaging magnification.
Although the technique of effecting magnification change in the compound eye optical system has heretofore been desired, a compound eye optical system having a variable magnification function has not been obtained because the compound eye optical system is not so simple as a single eye optical system and the conditions to be satisfied during magnification change are difficult. One of the conditions is that a multiimage of an object separately formed by a first minute imaging element array must be re-imaged as the only image on the image plane irrespective of the state of the lenses during magnification change and that the image plane must always be a plane conjugate with the object point relative to each unit imaging optical system forming the compound eye optical system.